Mass. Gen. Laws ch. 204, § 31

The word ''release'', as used in sections twenty-eight to thirty, inclusive, shall include (1) an instrument wherein the person who executes it in substance states that he wholly releases, or agrees in no respect to exercise or participate in the exercise of, a power of appointment, and (2) an instrument wherein the person who executes it in substance states that he releases all right to exercise or participate in the exercise of a power of appointment otherwise than within limits therein defined or agrees not to exercise or participate in the exercise of a power of appointment otherwise than within limits therein defined.